Deiodination of iodinated aromatic compounds with electrospray ionization mass spectrometry.

Rationale: Dehalogenation of iodinated X-ray contrast media (ICM) has been reported using electrochemical and bioelectrochemical systems. Correspondingly, dehalogenation of aromatic halogens has also been reported in mass spectrometry (MS) using different ionization techniques like chemical ionization (CI), thermospray, fast-atom bombardment (FAB) and FAB-liquid secondary ionization mass spectrometry (LSIMS). The aim of the present work was to study deiodination of iodinated aromatic compounds in MS with electrospray ionization (ESI).

Characterization of polysorbate 80 with liquid chromatography mass spectrometry and nuclear magnetic resonance spectroscopy: specific determination of oxidation products of thermally oxidized polysorbate 80.

The polysorbate species in polysorbate 80 (PS 80) have been characterized with (1)H NMR, LC-UV/MS and MS/MS. The MS was operated with both negative and positive electrospray ionization (ESI). PS 80 was found to contain mono- and di-fatty acid esters of polyoxyethylene (POE) sorbitan, POE isosorbide and of POE.

Effects of dietary thia fatty acids on lipid composition, morphology and macrophage function of Atlantic salmon (Salmo salar L.) kidney.

High lipid levels are being used in modern salmonid diets to promote rapid growth; however there is a limiting supply of the traditional fish oils as the fish farming industry expands. One way to utilize the lipid sources better, could be to find ways to stimulate fatty acid (FA) oxidation so that Atlantic salmon use more energy for muscle growth and less for storage in perivisceral adipose tissue. We have previously shown that dietary inclusion of the thia FA tetradecylthioacetic acid (TTA) promoted hepatic beta-oxidation and reduced total body lipid levels.

Phospholipid molecular species, beta-oxidation, desaturation and elongation of fatty acids in Atlantic salmon hepatocytes: effects of temperature and 3-thia fatty acids.

We have investigated the effects of a 3-thia fatty acid (TTA) and of temperature on the fatty acid (FA) metabolism of Atlantic salmon (Salmo salar). One experiment investigated the activity of the peroxisomal beta-oxidation enzyme, acyl-CoA oxidase (ACO), and the incorporation of TTA into phospholipid (PL) molecular species. Salmon hepatocytes in culture were incubated either without TTA (control(spades)) or with 0.

Quantification of phosphatidylserine, phosphatidic acid and free fatty acids in an ultrasound contrast agent by normal-phase high-performance liquid chromatography with evaporative light scattering detection.

Sonazoid is a new contrast agent for ultrasound imaging. The product is an aqueous suspension of perfluorobutane microbubbles coated with phospholipids obtained from hydrogenated egg phosphatidylserine (H-EPS). A normal-phase high-performance liquid chromatographic (HPLC) method with evaporative light scattering detection was developed for quantification of free fatty acids, phosphatidylserine and phosphatidic acid in H-EPS and Sonazoid.

Construction, evaluation and refinement of a large human antibody phage library based on the IgD and IgM variable gene repertoire.

The ability to isolate antibodies against any antigen of interest has become increasingly important as antibodies have proved their utility both in antigen detection, quantification and as specific in vivo targeting agents. To this end, we have constructed a large antibody phage library in the single chain Fv (scFv) phagemid format based on the naive human variable (V) gene repertoire dictated by IgD and IgM. Optimizing each step of the library construction has resulted in a highly diverse and functional library, as assessed by sequencing analysis, large-scale automated expression analysis and antigen screening.

Covalent antibody display--an in vitro antibody-DNA library selection system.

The endonuclease P2A initiates the DNA replication of the bacteriophage P2 by making a covalent bond with its own phosphate backbone. This enzyme has now been exploited as a new in vitro display tool for antibody fragments. We have constructed genetic fusions of P2A with single-chain antibodies (scFvs).

Effects of 3-thia fatty acids on feed intake, growth, tissue fatty acid composition, beta-oxidation and Na+,K+-ATPase activity in Atlantic salmon.

Atlantic salmon (Salmo salar) with an initial mass of 86 g were reared in 12 degrees C seawater for 8 weeks to a final average mass of 250 g. The fish were fed fish meal and fish oil-based diet supplemented with either 0%, 0.3% or 0.

Study of the reaction products of flavonols with 2,2-diphenyl-1-picrylhydrazyl using liquid chromatography coupled with negative electrospray ionization tandem mass spectrometry.

The products obtained after the reaction between flavonols and the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH(*)) in both methanol and acetonitrile were characterized using liquid chromatography coupled with negative electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) and NMR spectroscopy. The flavonols studied were quercetin, kaempferol and myricetin. In methanol, two reaction products of oxidized quercetin were identified using LC/ESI-MS/MS and NMR.

Neutralizing human antibodies to varicella-zoster virus (VZV) derived from a VZV patient recombinant antibody library.

Varicella-zoster virus (VZV), the causative agent of chickenpox and herpes zoster, can be life-threatening in prematurely born children and in children with immune defects or who are under immunosuppressive treatment. Therefore agents for passive immunization, such as VZV-specific immunoglobulin preparations (VZIG) derived from convalescent plasma, are crucial in the prophylaxis of VZV infection. This study describes the isolation of human VZV-neutralizing recombinant antibodies.

Analysis of flavonoids and other phenolic compounds using high-performance liquid chromatography with coulometric array detection: relationship to antioxidant activity.

High-performance liquid chromatography coupled with a coulometric array detector was used to characterize the electrochemical behavior of 17 flavonoids and three cinnamic acid derivatives. The antioxidant activity of these phenolic compounds was evaluated by the ferric reducing activity power (FRAP), the oxygen radical absorbance capacity (ORAC), and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assays. All flavonoids, except kaempferol-3-rutinoside, malvidin-3-glucoside, and peonidin-3-glucoside, had two oxidation potentials (100-300 and 700-800 mV).

Nature of the main contaminant in the anti malaria drug primaquine diphosphate: a qualitative isomer analysis.

The main contaminant of primaquine (CAS 90-34-6) has been tentatively identified, by using two liquid chromatography (LC) methods and liquid chromatography-mass spectrometry (LC-MS), as the positional isomer quinocide (CAS 525-61-1). The first LC system was equipped with a chiral Chirex (S)-VAL and (R)-NEA column and the second system was equipped with an Adsorbosphere Nucleotide-Nucleoside 7 micro column. Comparison of the main contaminant of primaquine with an authentic quinocide standard by using co-chromatography in both LC systems and LC-MS (mass fragmentation) supported the hypothesis.

Study of the collision-induced radical cleavage of flavonoid glycosides using negative electrospray ionization tandem quadrupole mass spectrometry.

Negative electrospray ionization tandem quadrupole mass spectrometry was used to study the collision-induced dissociation (CID) of the O-glycosidic bond from different commercially available flavonoid glycosides. Depending on the structure, flavonoid glycosides can undergo both a collision-induced homolytic and heterolytic cleavage of the O-glycosidic bond producing deprotonated radical aglycone ((Y(0) - H)(-*)) and aglycone (Y(0) (-)) product ions. The relative abundance of the radical aglycone to the aglycone fragment from flavonol-3-O-glycosides increased with increasing number of hydroxyl substituents in the B ring and in the order kaempferol - View Article and Find Full Text PDF

Separation and identification of phosphatidylserine molecular species using reversed-phase high-performance liquid chromatography with evaporative light scattering and mass spectrometric detection.

A reversed-phase HPLC method compatible with evaporative light scattering (ELS) and electrospray mass spectrometric (ES-MS) detection was developed for separation of phosphatidylserine (PS) molecular species. The method was optimised for separation of three disaturated synthetic species: dipalmitoyl glycerophosphoserine, palmitoyl-stearoyl glycerophosphoserine and distearoyl glycerophosphoserine using isocratic elution with a mixture of 2-propanol, tetrahydrofuran and ammonium formate. Baseline separation was obtained on three different columns: one polystyrene/divinylbenzene (PS/DVB) column and two silica based C(18) and C(30) columns.

Determination of phenolic compounds in rose hip (Rosa canina) using liquid chromatography coupled to electrospray ionisation tandem mass spectrometry and diode-array detection.

Liquid chromatography coupled with negative and positive electrospray ionisation (ESI) tandem mass spectrometry (MS/MS) and diode-array detection (DAD) was used for determination of phenols in rose hip (Rosa canina) extract. ESI mass spectra of the chromatographically separated phenols gave the molecular weight of the compounds through prominent [M - H](-) ions for most of the compounds and M(+) ions for the anthocyanins. Collision induced dissociation (CID) of the [M - H](-) (or M(+)) precursor ions yielded product ions which determined the molecular weight of the aglycones.

A systematic screening of total antioxidants in dietary plants.

A predominantly plant-based diet reduces the risk for development of several chronic diseases. It is often assumed that antioxidants contribute to this protection, but results from intervention trials with single antioxidants administered as supplements quite consistently do not support any benefit. Because dietary plants contain several hundred different antioxidants, it would be useful to know the total concentration of electron-donating antioxidants (i.

Determination of perfluorobutane in rat blood by automatic headspace capillary gas chromatography and selected ion monitoring mass spectrometry.

A new contrast agent (Sonazoid; NC100100) for ultrasound imaging has been developed. It is an aqueous suspension of lipid stabilised perfluorobutane (PFB) gas microbubbles. An automatic headspace capillary gas-chromatographic mass spectrometric method using electron impact ionisation was developed for analysis of Sonazoid PFB in rat blood.

Analysis of triacylglycerols with non-aqueous reversed-phase liquid chromatography and positive ion electrospray tandem mass spectrometry.

A non-aqueous reversed-phase liquid chromatographic method coupled to electrospray ionisation (ESI) tandem mass spectrometry was developed for the analysis of triacylglycerols (TGs). The synthetic TGs studied were separated according to their equivalent carbon number with a gradient of methanol (containing 0.01% (v/v) formate adjusted to pH 5.

Effect of soybean oil and fish oil on individual molecular species of Atlantic salmon head kidney phospholipids determined by normal-phase liquid chromatography coupled to negative ion electrospray tandem mass spectrometry.

The effect of soybean oil (SO) and fish oil (FO) on the relative molecular species distribution of phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI) and phosphatidylserine (PS) in Atlantic salmon head kidney was studied using normal-phase liquid chromatography coupled with negative ion electrospray tandem mass spectrometry. The conformation of identity of the phospholipid species was based on retention time, the mass of the [M-H]- ([M-15]- for PC) molecular ions and the carboxylate anion fragments in the product ion spectrum. The intensity ratio of sn-1/sn-2 fragment ions increased with increasing number of double bonds in the sn-2 acyl chain but was not affected by increasing number of double bonds in the sn-1 acyl chain of the species examined.

Intravenous bilirubin, dibromosulfophthalein, and bromosulfophthalein infusions uncouple biliary phospholipid and cholesterol secretion from bile acid secretion by inhibiting hepatic phosphoglycoprotein-3 activity in pigs.

Background: Biliary secretion of organic anions disturbs the proportional relationship normally pertaining between biliary lipid and bile acid secretion. The mechanism causing this uncoupling of biliary lipid from bile acid secretion is incompletely understood. Impaired micellization of membrane lipids by bile due to biliary contamination with organic anions or lowering of biliary bile acid concentration by enhanced bile acid-independent bile flow has been proposed as causative factors.

Effect of intravenous bilirubin infusion on biliary phospholipid secretion, hepatic P-glycoprotein expression, and biliary cytotoxicity in pigs.

Background: Infusion of large intravenous bilirubin loads in bile acid-depleted pigs reduces P-glycoprotein-dependent biliary phospholipid secretion and increases the cytotoxicity of bile. The reasons for the diminution of biliary phospholipid secretion and the increase in biliary cytotoxicity are not known. This study was undertaken to determine whether the bilirubin-induced lowering of biliary phospholipid secretion is associated with alterations in hepatic P-glycoprotein (P-gp) expression and to determine why bilirubin infusions increase biliary cytotoxicity.

Lipopolysaccharide from Actinobacillus actinomycetemcomitans stimulates production of interleukin-1beta, tumor necrosis factor-alpha, interleukin-6 and interleukin-1 receptor antagonist in human whole blood.

Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) is supposed to be an important etiological agent in localized juvenile periodontitis (LJP). We have studied the effect of lipopolysaccharide (LPS) extracted from these periodontopathogenic bacteria on synthesis of the proinflammatory cytokines, interleukin-1beta(IL-1beta), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and the anti-inflammatory cytokine IL-1 receptor antagonist (IL-1ra) in human whole blood.

Specific detection and quantification of palmitoyl-stearoyl-phosphatidylserine in human blood using normal-phase liquid chromatography coupled with electrospray mass spectrometry.

A narrow-bore normal-phase high-performance liquid chromatography (HPLC) method was developed for separation of phospholipid classes using an HPLC diol column and a gradient of chloroform and methanol with 0.2% formic acid titrated to pH 5.3 with ammonia.

Study of mechanisms involved in the collision-induced dissociation of carboxylate anions from glycerophospholipids using negative ion electrospray tandem quadrupole mass spectrometry.

The collision-induced dissociation of the carboxylate anions from human blood phosphatdilycholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI) and phosphatidic acid (PA) containing the C18:0 (sn-1) and C20:4 (sn-2) fatty acyl residues was studied using normal phase liquid chromatography coupled with negative ion electrospray tandem mass spectrometry. The product ion peak area ratio of C18:0 to C20:4 was calculated for each phospholipid species and was found to increase with increasing collision energy for all classes. For the phospholipids with a net neutral charge (PE, PC) there was a preferential loss of the sn-2 carboxylate anion (C20:4) at low collision energy, while at higher energy there was a preferential loss of the sn-1 carboxylate anion (C18:0).

Large intravenous bilirubin loads increase the cytotoxicity of bile and lower the resistance of the canalicular membrane to cytotoxic injury and cause cholestasis in pigs.

Background: Large intravenous bilirubin loads cause loss of hepatic canalicular membrane microvilli and cholestasis. This study examines whether these untoward effects might be due to canalicular membrane injury from cytotoxic bile.

Methods: The cytotoxicity of bile was assayed against pig erythrocytes before and throughout 4.